code: def iter_grid(n_rows, n_cols):
      # create a grid using gradio Block
      for _ in range(n_rows):
          with gr.Row():
              for _ in range(n_cols):
                  with gr.Column():
                      yield
  
imports: import gradio
  import math
  from functools import partial
  import matplotlib.pyplot
  import numpy
  from sklearn.cluster import AgglomerativeClustering, Birch, DBSCAN, KMeans, MeanShift, OPTICS, SpectralClustering, estimate_bandwidth
  from sklearn.datasets import make_blobs, make_circles, make_moons
  from sklearn.mixture import GaussianMixture
  from sklearn.neighbors import kneighbors_graph
  from sklearn.preprocessing import StandardScaler
label_desc: Use image node_id 20 for calling a global function with example usage: iter_grid(n_rows, n_cols) without return types